In a little more than two months, the FBI plans to pull the plug on DNS servers that are currently providing PCs infected with the DNS Changer malware with the ability to translate domain names into IP addresses.

How prevalent is DNS Changer? Rod Rasmussen, a member of the DNS Changer Working Group, said that in early February 2012, the malware was infecting machines used by half of all Fortune 500 companies as well as 27 out of 55 government agencies. But by the end of that month, he said that infection rates appeared to have dropped to 94 companies and just three agencies.

The criminals allegedly used the malware to reroute infected machines to their own rogue DNS servers. That meant that even after the FBI helped bust the suspected botnet operators, anyone whose machine was infected with the malware would still be relying on the rogue DNS servers to be able to surf the Internet.

Accordingly, the bureau said that it would continue to support the DNS servers for another four months, although it disabled the command-and-control infrastructure underlying the botnet and said it wasn't monitoring any of the traffic traveling over the DNS servers. In addition, the FBI said that it had "provided information to ISPs that can be used to redirect their users from the rogue DNS servers to the ISPs' own legitimate servers."

With that deadline fast approaching, however, and many machines apparently still infected with DNS Changer, on March 12 the FBI secured a court order "authorizing the Internet Systems Consortium (ISC) to deploy and maintain temporary clean DNS servers," according to a statement released by the FBI.

Because this solution costs money, it's temporary and is intended only to buy "additional time for victims to clean affected computers and restore their normal DNS settings," according to the FBI. "The clean DNS servers will be turned off on July 9, 2012, and computers still impacted by DNSChanger may lose Internet connectivity at that time."

In other words, anyone whose machine is infected with the malware has about two months left to eradicate it or lose Internet access. At that point, to eliminate the malware and restore their correct DNS settings, users will need to download antivirus software--using another PC--and install it on their PC; for example, by using a USB key.

Hacktivist and cybercriminal threats concern IT teams most, our first Federal Government Cybersecurity Survey reveals. Here's how they're fighting back. Also in the new, all-digital Top Federal IT Threats issue of InformqtionWeek Government: Why federal efforts to cut IT costs don't go far enough, and how the State Department is enhancing security. (Free registration required.)